1. Field of the Invention
The present invention relates to a system for monitoring the population in a room using a device such as a television. More particularly, the present invention relates to such a monitoring system in which the entry into or exit from the room is monitored.
2. Description of the Prior Art
The prior art is replete with various systems and arrangements for monitoring the use of devices. An example is monitoring the channel tuning habits of television viewers. The earliest such systems merely collected the data on site for eventual manual collection as to the television channels viewed and the times of viewing for various panels of viewers in order to determine market share and ratings of various television programs. Later, systems came into being for use with cable television systems with two-way communications over the cable system between the head end and various cable subscribers. In such a system, the television sets were typically interrogated periodically from the central location over the cable, with the channel selection and time information being sent back to the central location and logged for statistical compilation. Such systems have also been used in the past in pay television systems in which billing information was sent over the cable system from a central location to the various subscribers of the pay television system. The prior art also includes such systems in which a memory was provided at the remote location, i.e., at the television receiver, for accumulating data as to the channel being tuned in at the time. The accumulated data was then periodically transmitted over conventional telephone lines from the remote locations to the central location by telephone calls initiated by either the remote stations or the central location.
Systems for remotely accumulating data regarding the habits of television viewers and their qualitative reaction to television programming have today become important from the standpoint of market research. Several prior art systems enable the viewer's preferences to be monitored. For example, the effectiveness of television programming can be monitored by remote control devices used by audience members who may enter their reaction to broadcast programs displayed on their television screens. Such systems are disclosed in U.S. Pat. Nos. 4,107,734 and 4,308,554, both to Percy et al. In these systems, the information received by the remote control device is inputted to a localized interrogator and later dumped to a central computer. This apparatus may be used for determining which channel the set is on and viewer reactions to the displayed broadcast over that channel.
Another approach of the prior art has been to use "people meters". With these people meters, each television set is furnished with one or more remote-control devices which are pressed at the start and finish of viewing to record each person's watching patterns. Thus, this system operates effectively as an electronic diary in which the television viewing patterns of each individual are recorded. As the demands for more precise information about the individual viewers' habits and preferences developed, however, such electronic diaries were no longer sufficient.
Advertising agencies, who buy billions of dollars worth of commercial time on the main networks each year, want to know not only the number of homes with television sets tuned to a particular program, but the actual number of people watching a particular show. With that information, and with breakdowns of sex, age and income, ad agencies will be better able to tell their clients how to reach the viewer they want. As a result, viewer interactive devices such as that disclosed in U.S. patent application Ser. No. 658,378, now U.S. Pat. No. 4,658,290 to McKenna et al., incorporated herein by reference, have developed. The data gathering system of McKenna, for example, utilizes an elapsed time clock to generate prompts at predetermined intervals of time, and the viewer may respond to these prompts by inputting the desired information. In operation, the McKenna system flashes a message on a television screen every thirty minutes or so that asks "Who's watching?" . The message will not go away until viewers punch in codes on an attached keypad reporting the individuals in the room so that the system can determine the age and sex of everyone in the room. The McKenna system, therefore, automatically provides prompts at periodic intervals to remind people viewing the television set to push the keys if persons have entered or left the vicinity of the television set since the keys were previously pushed, or to confirm that the viewers have not changed. This system has several shortcomings, however, which it is the purpose of the present invention to correct. Such short-comings include:
1. When persons arrive or depart, they may fail to push the appropriate keys, i.e., to immediately enter the required information without waiting to be prompted to do so. This is especially the case with small children. Such a failure obviously reduces the accuracy of data collected.
2. When a prompt automatically occurs, the persons may push the buttons which confirm no change in viewers, despite the fact that persons have actually arrived or departed since the last previous key entries were made. The resulting deficiencies in the received information are commonly handled by computer editing procedures which make certain assumptions about arrivals, departures, or absence of change. Consequently, the entire resulting file of data concerning viewing by people is suspect. In particular, the value of the data is depreciated when its user desires accurate knowledge of the size and composition of the audience that was exposed to a particular advertising message which was aired during a specific 15 or 30 second interval.
3. Since these systems require active and continuous cooperation by members of the household, many households refuse to allow their installation. Others tire of the activity imposed on them and demand that the monitoring equipment be removed. The result may be the injection of what sampling statisticians call "non-response bias", which can be fatal to the usability and acceptance of the overall audience estimates produced by the system. For these reasons, operators of television audience measurement systems offer financial incentives to induce the pre-selected sample households to allow installation of the equipment and to continue its use. The effectiveness of these incentives, however, usually varies inversely with the socio-economic status of the households and with their values and attitudes. Hence, non-response bias may persist, despite the high cost of the financial incentives to the system operators. Obtaining and maintaining the cooperation of various types of households (those of single persons, the aged, certain ethnic populations, etc.) is also a continuing problem.